package com.heima.schedule.service.impl;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.heima.common.constants.ScheduleConstants;
import com.heima.common.redis.CacheService;
import com.heima.model.schedule.dtos.Task;
import com.heima.model.schedule.pojos.Taskinfo;
import com.heima.model.schedule.pojos.TaskinfoLogs;
import com.heima.schedule.mapper.TaskinfoLogsMapper;
import com.heima.schedule.mapper.TaskinfoMapper;
import com.heima.schedule.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Set;

/**
 * @author tmh
 * @date 2023/8/23 14:31
 * @description
 */
@Service
@Slf4j
@Transactional
public class TaskServiceImpl implements TaskService {
    /**
     * 添加延迟任务
     *
     * @param task 任务对象
     * @return
     */
    @Override
    public long addTask(Task task) {
        //1.添加任务到数据库中
        boolean success = addTaskToDb(task);

        //2.把任务添加到redis里面
        if (success) {
            //2.添加任务到redis
            addTaskToCache(task);
        }


        return task.getTaskId();
    }

    @Autowired
    private CacheService cacheService;

    /**
     * 把任务添加到redis里面
     *
     * @param task
     */
    private void addTaskToCache(Task task) {
        String key = task.getTaskType() + "_" + task.getPriority();
        //获取五分钟之后的时间，毫秒值
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE, 5);
        long nextScheduleTime = calendar.getTimeInMillis();
        //2.1如果任务的执行时间小于当前时间，存入list
        if (task.getExecuteTime() <= System.currentTimeMillis()) {
            cacheService.lLeftPush(ScheduleConstants.TOPIC + key, JSON.toJSONString(task));
        } else if (task.getExecuteTime() <= nextScheduleTime) {
            //2.2 如果任务的执行时间大于当前时间 && 小于等于预设时间（未来5分钟） 存入zset中
            cacheService.zAdd(ScheduleConstants.FUTURE + "_" + key, JSON.toJSONString(task), task.getExecuteTime());
        }
    }

    @Resource
    private TaskinfoMapper taskinfoMapper;

    @Resource
    private TaskinfoLogsMapper taskinfoLogsMapper;

    /**
     * 把任务添加到数据库中
     *
     * @param task
     * @return
     */
    private boolean addTaskToDb(Task task) {
        boolean flag = false;
        try {
            //保存任务表
            Taskinfo taskinfo = new Taskinfo();
            BeanUtils.copyProperties(task, taskinfo);
            taskinfo.setExecuteTime(new Date(task.getExecuteTime()));
            taskinfoMapper.insert(taskinfo);
            //设置taskId
            task.setTaskId(taskinfo.getTaskId());
            //保存任务日志数据
            TaskinfoLogs taskinfoLogs = new TaskinfoLogs();
            BeanUtils.copyProperties(taskinfo, taskinfoLogs);
            taskinfoLogs.setVersion(1);
            taskinfoLogs.setStatus(ScheduleConstants.SCHEDULED);
            taskinfoLogsMapper.insert(taskinfoLogs);
            flag = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

    /**
     * 取消任务
     *
     * @param taskId
     * @return
     */
    @Override
    public boolean cancelTask(long taskId) {
        boolean flag = false;
        //删除任务，更新日志
        Task task = updateDb(taskId, ScheduleConstants.CANCELLED);
        //删除redis的数据
        if (task != null) {
            removeTaskFromCache(task);
            flag = true;
        }
        return flag;
    }


    /**
     * 按照类型和优先级拉取任务
     *
     * @param type
     * @param priority
     * @return
     */
    @Override
    public Task poll(int type, int priority) {
        Task task = null;
        try {
            String key = type + "_" + priority;
            String task_json = cacheService.lRightPop(ScheduleConstants.TOPIC + key);
            if (StringUtils.isNotBlank(task_json)) {
                task = JSON.parseObject(task_json, Task.class);
                //更新数据库信息
                updateDb(task.getTaskId(), ScheduleConstants.EXECUTED);
            }
        } catch (Exception e) {
            e.printStackTrace();
            log.error("poll task exception");
        }
        return task;
    }

    /**
     * 删除redis里面的数据
     *
     * @param task
     */
    private void removeTaskFromCache(Task task) {
        String key = task.getTaskType() + "_" + task.getPriority();
        if (task.getExecuteTime() <= System.currentTimeMillis()) {
            cacheService.lRemove(ScheduleConstants.TOPIC + key, 0, JSON.toJSONString(task));
        } else {
            //这里的else我感觉有点多余，可能是因为可以手动取消任务吧，继续往后面看
            cacheService.zRemove(ScheduleConstants.FUTURE + key, JSON.toJSON(task));
        }
    }

    /**
     * 删除任务，更新日志状态
     *
     * @param taskId
     * @param status
     * @return
     */
    private Task updateDb(long taskId, int status) {
        Task task = null;
        try {
            //删除任务
            taskinfoMapper.deleteById(taskId);
            //修改日志表里面的状态
            TaskinfoLogs taskinfoLogs = taskinfoLogsMapper.selectById(taskId);
            taskinfoLogs.setStatus(status);
            taskinfoLogsMapper.updateById(taskinfoLogs);

            task = new Task();
            BeanUtils.copyProperties(taskinfoLogs, task);
            task.setExecuteTime(taskinfoLogs.getExecuteTime().getTime());
        } catch (Exception e) {
            log.error("task cancel exception taskId", taskId);
        }
        return task;
    }

    /**
     * 未来数据定时刷新
     */
    @Scheduled(cron = "0 */1 * * * ?")
    public void refresh() {

        String token = cacheService.tryLock("FUTURE_TASK_SYNC", 1000 * 30);

        if (StringUtils.isNotBlank(token)) {
            log.info("未来数据定时刷新---定时任务");

            //获取所有未来数据集合的key值
            Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");
            for (String futureKey : futureKeys) {
                String topicKey = ScheduleConstants.TOPIC + futureKey.split(ScheduleConstants.FUTURE)[1];
                //获取该组key下需要消费的任务数据
                Set<String> tasks = cacheService.zRangeByScore(futureKey, 0, System.currentTimeMillis());
                if (!tasks.isEmpty()) {
                    //将这些数据刷新到消费队列中
                    cacheService.refreshWithPipeline(futureKey, topicKey, tasks);
                    log.info("成功的将" + futureKey + "下的当前需要执行的任务数据刷新到" + topicKey + "下");
                }
            }
        }
    }

    /**
     * 数据库同步到缓存
     */
    @Scheduled(cron = "0 */5 * * * ?")
    @PostConstruct//一开始就执行一次
    public void reloadData(){
        //如果不清除缓存，就会造成redis里面数据重复的问题
        clearCache();
        log.info("数据库同步到缓存中");
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE,5);

        //查看小于未来五分钟的所有任务
        List<Taskinfo> allTasks = taskinfoMapper.selectList(Wrappers.<Taskinfo>lambdaQuery()
                .lt(Taskinfo::getExecuteTime, calendar.getTime()));
        //新增任务到redis
        for (Taskinfo allTask : allTasks) {
            Task task = new Task();
            BeanUtils.copyProperties(allTask,task);
            task.setExecuteTime(allTask.getExecuteTime().getTime());
            addTaskToCache(task);
        }
    }

    /**
     * 清除缓存
     *
     */
    public void clearCache(){
        //删除缓存在未来数据集合和当前消费者队列的所有key
        Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");
        Set<String> topicKeys = cacheService.scan(ScheduleConstants.TOPIC + "*");
        cacheService.delete(futureKeys);
        cacheService.delete(topicKeys);
    }
}
